Hitherto, for example, there has been known a charging management device disclosed in Patent Literature 1. This related-art charging management device is installed in a vehicle including an in-vehicle battery to be used as an electric power supply for in-vehicle devices and a solar cell for charging the in-vehicle battery. The solar cell is also capable of being used to charge a rechargeable battery for external devices to be used as an electric power supply to devices external to the vehicle. As a result, for example, when the in-vehicle battery is fully charged, the rechargeable battery for external devices can be charged by the solar cell, enabling the electric power generated by the solar cell installed in the vehicle to be used more efficiently.
Further, hitherto, for example, there has also been known a vehicular power supply control device disclosed in Patent Literature 2. This related-art vehicular power supply control device includes an in-vehicle battery configured to supply electric power to a load group and a solar cell configured to charge the in-vehicle battery using generated electric power. The vehicular power supply control device also includes a storage device configured to store the electric power generated by the solar cell, a switch circuit configured to switch a connection between the solar cell and storage device and the in-vehicle battery on or off, and an operation unit configured to switch the switch circuit on or off.
In addition, hitherto, for example, there has also been known an electric vehicle disclosed in Patent Literature 3. This related-art electric vehicle includes a high-voltage battery configured to drive an electric motor for driving the vehicle, a solar cell, a DC/DC converter for charging configured to supply electric power generated by the solar cell to the high-voltage battery, a charging control electronic control unit (ECU) configured to perform charging control of the high-voltage battery on the DC/DC converter for charging, and a low-voltage power supply DC/DC converter configured to receive a portion of the electric power generated by the solar cell and generate a power supply voltage to be supplied to the charging control ECU.
Still further, hitherto, for example, there has also been known an electric vehicle charging system disclosed in Patent Literature 4. This related-art electric vehicle charging system includes a plurality of solar cell modules formed by wiring solar cell elements together in series so that when sufficient solar light is shone on the solar cell elements, a charging voltage capable of directly charging an auxiliary battery is produced. When the output voltage of the solar cell modules is high, the auxiliary battery is directly charged, and when the output voltage is low, a main battery is charged via a DC/DC converter.
Even still further, hitherto, for example, there has also been known a hybrid vehicle energy regeneration device disclosed in Patent Literature 5. This related-art hybrid vehicle energy regeneration device is configured to store electric power having a large load change generated by regenerative braking of an electric motor during deceleration or electric power generated by a solar cell to an electric dual capacitor. The stored electric power is increased to a predetermined voltage via a charger, and then re-stored in a battery including a lithium ion cell.
Yet even still further, hitherto, for example, there has also been known an electric vehicle control device disclosed in Patent Literature 6. This related-art electric vehicle control device includes a main battery configured to supply electric power to a motor, a first auxiliary battery configured to supply electric power to an electric device in the vehicle, a step-up/step-down transformer configured to step-up and step-down electric power between a drive system circuit and the first auxiliary battery and supply the stepped-up/stepped-down electric power in both directions, a solar panel configured to charge the first auxiliary battery, and a battery control unit configured to control charging and discharging by monitoring remaining levels of the main battery and the first auxiliary battery. Further, in this related-art electric vehicle control device, the battery control unit charges the first auxiliary battery using the solar panel. When the remaining level of the first auxiliary battery reaches a first predetermined value, the battery control unit charges the main battery by increasing the voltage of the electric power of the first auxiliary battery with the step-up/step-down transformer.